Tag Archives: Epigenetic change

An article in the journal Science speaks about orphanages in Pakistan, and of the many children there whose mothers, unable to find paid work in that very conservative society, have been obliged to surrender them. Understandably, these children sometimes show symptoms similar to post-traumatic stress disorder, including anxiety and depression. That’s not the only unhappy human scene touched upon in the article, although it’s the only present-day one. The author, Andrew Curry, also speaks of the 1945 famine in Holland, of the Holocaust, and of the American Civil War – a strange assortment of very good reasons to pity the human experience.

The article is titled ‘A Painful Legacy’, because what brings these disasters together in a science journal is the hypothesis that stress and emotional trauma may alter biology in ways that can be transmitted to succeeding generations: not directly, by altering genes themselves, but by modifying the epigenome, defined in the article as “a swirl of biological factors that affect how genes are expressed”. Studies of the children of parents that have suffered in such disasters have discovered “subtle biological alterations – changes so lasting that children might even pass them to their own offspring.” If that really is happening, some revision of evolutionary theory may be necessary, incorporating to some degree the inheritance of acquired characteristics – of undesired and unfavourable ones, at least.

But the word ‘pain’ is always a sort of skull and crossbones for the reader of science journals: it signals vivisection. Whether or not humans do pass their misery down the generations, modern research habitually makes sure that other animal species inherit it, forcing them to try out our pain for us. Most cruelly and haphazardly is this so when the pain in question is the sort suffered by the mind, as in the present instance. And sure enough, the first word of this article’s sub-title is “Mice …” So yes, it’s mice being made to suffer, although mention is also made of experiments on rats, crickets, worms, water fleas, more vaguely “many organisms”, and even more casually just “animals”. (The author mostly calls humans “people”, a non-scientific word which helps to keep us categorically distinct from this scene of zoological service and sacrifice.)

Heredity being the theme, the target of the so-called “mouse intervention” is motherhood. The scientist principally featured in the article, Professor Isabelle Mansuy of Zurich University – a woman, you’ll notice – “separates mouse mothers from their pups at unpredictable intervals and further disrupts parenting by confining the mothers in tubes or dropping them in water, both stressful experiences for mice [in case you wondered].” And this account, unpleasantly reminiscent of Harry Harlow’s notorious experiments with monkeys, continues thus:

When the mothers return to the cage and their pups, they’re frantic and distracted. They often ignore the pups, compounding the stress of the separation on their offspring.

Actually there is a brief pause for ethics after that unsavoury pair of sentences. Two lines of the article reassure us that this contrived misery “has a purpose”, which is “to gain understanding for better child health”.

We aren’t given much reason to expect this purpose to be achieved (and of course, as this article celebrating the work implies, the success of the science and of the scientists does not depend on practical results). For a start there’s the obvious and familiar reservation, expressed already in the second word of the sub-title: “Mice hint at how people’s emotional trauma may affect the biology of their children.” It can only be a hint, for as Professor Mansuy admits, in a break from tormenting her mouse families, “mice and people are different, showing the limits of mouse models.” Among other discontinuities, human histories are full of personal and social unknowns, producing ills whose causes can’t be conveniently traced and measured like the ones which Professor Mansuy devises. Her solution is to look for the right sort of humans, people whose life stories (says Curry) “have similarities to what the mice in Mansuy’s lab experience.” So now we’re looking about for humans to go with the mice!

But let’s suppose that these “epigenetic effects” are indeed confirmed in humans. How will the discovery be made beneficial to them? Curry does his best to make a dramatic ‘breakthrough’ story of it all, with some atmospherics (“Mansuy donned a fresh lab coat . . . and gently cracked the door of a darkened room at her lab at UZH.”) and helpful hyperbole: “really scary stuff”, says another scientist about the idea that “the things we’re doing today, that we thought were erased, are affecting our great-great-grandchildren.” Actually it’s rather a familiar idea, isn’t it? At any rate, it’s mooted in the Bible, and is plainer than ever now that the industrial revolution is afflicting its latter generations with climate change. However, “The implications are profound”, Curry insists; they constitute “a powerful argument against everything from smoking to immigration policies that split families.” So for those of us who had always suspected that smoking and splitting families, to say nothing of famine and civil war, were bad things, but couldn’t explain quite why – well, we’re now scientifically vindicated.

But what if, even now that we’re furnished with this “powerful argument”, we can’t always stop these things from happening? Can this science tell us how to prevent or cure their malign effects in later generations? Again there’s a sort of drum-roll in the article: “In a darkened room down the hall from Mansuy’s office, just outside the mouse breeding area, two cages stand side by side on a table . . .” One of the cages is the standard featureless box endured by countless generations of lab mice as their perfunctory home. The other is ‘enriched’ with play-wheels and a maze; it even has an upstairs. It seems that “traumatized mice raised in this enriched environment don’t pass the symptoms of trauma to their offspring”. And perhaps epigenetic change is not just preventable in this way, with equivalents of enriched environment, but actually “reversible”. That makes sense, after all, for as another scientist is quoted as saying, “If it’s epigenetic, it’s responsive to the environment”, which ought to mean good environments as well as bad. And indeed, Professor Mansuy’s research suggests that “life experience can be healing as well as hurtful.” Mirabile dictu!

Returning to the orphanages in Pakistan: we were told at the start of the article that the children there already get “the best possible support”. So the science of the matter as described by Andrew Curry, with all its equipment and expertise, seems to have taken us on a grand tour of predatory experiment and gratuitous suffering, and then landed us back where we were before, using our ordinary common sense and human decency. Well, not quite back there yet, because it’s all still hypothetical. As a geneticist at the finely-named Albert Einstein College of Medicine in New York warns us, there have been no “definitive studies, even in mice”; we need to be “open to the idea that there may be nothing there.” And Professor Mansuy doesn’t deny it; fortunately for all involved – for the ‘people’ involved, that is – “there’s lots more work to be done.” Of course, there always is, and lots more mice, crickets, and other innocents for it to be done on.

Meanwhile I guess that we should go on giving the orphans and other human legatees of sorrow the best possible support, until we know better.

Notes and references:

‘A Painful Legacy’, written by the journalist Andrew Curry, was published in Science, 19 July 2019, pp.212-15.